Hi Folks,
I have just joined the fourm and have am hoping I might be able to get some advice about my sick MS460.
The brief history of the problem is as follows. The saw stopped working about a month ago whilst i was using it, I didn't have time to look into it then but I suspected the piston had siezed in the barrel (pull cord was tight etc).
I have since stripped barrel and piston out of it and found that the piston has two deep sctatches on the intake side (the back of the piston when its in the saw I think!)
Pic 1 shows the scratches, and the piston had quite a lot of black residue on the exhaust side shown in pic 2
The condition of the barrel is shown in the following 3 pictures, other than what can be seen it has two rough lumps that would match with the scratches in the piston.
As to the cause I' a bit lost, the only thing I had done differently with the saw was at a job when I ran out of two stroke so went to B&Q and bought a one shot 50:1 two stoke oil mix. it wasn't a stihl, oregon etc brand of oil but i figured it would be ok, I will have ran about 5litres of the mix through this saw, so I'm wondering if that might have done the damage.
Other than that whilst stripping it down I noticed one of the circlips that holds the piston in place on the crank had one of the turned in ends missing, so i wondered if this might have found its way in to the barrel?
I'm wondering if
(1. Do I need to replace the piston and barrel, or could get away with a new piston and cleaning up the barrel?
(2. Is it likely to have been caused by the oil i used or do I need to investigate for other problems?
If anyone has any thoughts or advice I'd be really grateful to hear them as its my first real exploration into the internal workings of a chain saw! Also its a great saw and a shame to have it out of action.
Many thanks
John